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Analysis of a Water-Cooled Unit under Different Loads

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Fluid Dynamics & Materials Processing 2023年第7期19卷 1863-1873页

作者： Daoming Shen jinhong xia Chao Gui Songtao Xue Xinxiang University Xinxiang453000China Department of Architecture Tohoku Institute of TechnologySendai982-8577Japan

In order to ensure the safe operation of the compressors used in water chillers,in the present study some interlock protections have been added to the related design.These include a low pressure protection,a high pressure protection,an exhaust temperature protection and a differential pressure protection.Some tests have been conducted by tuning the saturation suction and exhaust temperatures of the compressor through adjustment of the cold source outlet temperature and the ambient temperature.The results show that the ambient temperature increases with decreasing device load and increasing fan speed under the same saturated suction temperature;the device refrigerating capacity steps up with augmenting load and dropping saturation exhaust temperature,while it is not greatly affected by the fan speed.Moreover,the Energy efficiency ratio(COP)decreases with the rise of the saturation exhaust temperature.This parameter is not affected much by the device load and fan speed at high saturation exhaust temperature,while it improves on increasing the device load and decreasing the fan speed at low saturation exhaust temperature.

关键词： Ambient temperature cold source temperature refrigerating capacity Energy efficiency ratio(COP) fan speed load

Microscopic Simulation of Expansive Soils and Evolution Laws

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Fluid Dynamics & Materials Processing 2020年第6期16卷 152-161页

作者： Lin Pan jinhong xia Hongxing Han School of Civil Engineering and Architecture Xinxiang UniversityXinxiang453003China

In this paper,the discrete element method(DEM)is used to study the microstructure of expansive soils.The results of the numerical calculations are in agreement with the stress-strain triaxial test curve that is obtained for a representative expansive soil.Biaxial compression tests are conducted for different confining pressures(50 kpa,100 kpa,and 150 kpa).Attention is paid to the following aspects:deviatoric stress,boundary energy,friction energy,bond energy,strain energy,kinetic energy,and the contact force between grains when the test specimen is strained and to the effect of the different confining pressures on the internal crack expansion.The results of this research show that the cross-section of the specimen is destroyed along the middle part of the specimen itself.When the confining pressure is higher,the impulse is stronger,and this leads to more effective destruction.

关键词： Expansive soil particle flow parallel-bond crack

A Water-Heat-Force Coupled Framework for the Preparation of Soils for Application in Frozen Soil Model Test

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Fluid Dynamics & Materials Processing 2021年第1期17卷 21-37页

作者： Daoming Shen xia Zhang jinhong xia Shunqun Li College of Civil Engineering and Architecture Xinxiang UniversityXinxiang453000China School of Journalism and Communication Xinxiang UniversityXinxiang453000China College of Civil Engineering and Architecture Tianjin Chengjian UniversityTianjin300384China

The freezing of soil containing a liquid is a complex transient heat conduction problem involving phase change and release or absorption of latent heat.Existing efforts have essentially focused on theoretical research and numerical simulations.In the present study,the problem is approached from an experimental point of view using the so-called“freezing model test”method.In particular,in order to establish a precise relationship between the model and the prototype,a temperature similarity criterion is derived using the condition of an equal number of Kosovitch.Similarity is also established with respect to other aspects.A similarity criterion for the water field is determined on the basis of relevant partial differential equations.Analogous criteria for the stress field and load are derived using an elastic model.The validity of this approach is experimentally verified.The research results provide a practical and reasonable method for calculating the parameters for preparing model soils.They also constitute a theoretical basis and a technical support for the design and implementation of a water-heat-force similarity coupled framework.

关键词： Latent heat frozen soil temperature field water-heat-force coupled framework

Heat Transfer Enhancement Using R1234yf Refrigerants in Micro-Ribbed Tubes in a Two-Phase Flow Regime

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Fluid Dynamics & Materials Processing 2020年第6期16卷 192-205页

作者： Daoming Shen xia Zhang Wei He jinhong xia Songtao Xue School of Civil Engineering&Architecture Xinxiang UniversityXinxiangChina Department of Architecture Tohoku Institute of TechnologySendai982-8577Japan

Experiments about heat transfer in the presence of a two-phase flow due to the condensation of a R1234yf refrigerant have been performed considering a smooth tube and two micro-fin tubes.The following experimental conditions have been considered:Condensation temperatures of 40℃,43℃ and 45℃,mass fluxes of 500–900 kg/(m^(2)·s),vapor qualities at the inlet and outlet of the heat transfer tube in the ranges 0.8–0.9 and 0.2–0.3,respectively.These tests have shown that:(1)The heat transfer coefficient increases with decreasing the condensation temperature and on increasing the mass flux;(2)The heat transfer coefficient inside the micro-fin tube is larger than that for the smooth tube;(3)The heat transfer enhancement factors for the micro-fin tube with a fin helical angle of 8°and 15°are 2.51–2.89 and 3.11–3.57,respectively;both are higher than the area increase ratio.These experimental results have been compared with correlations available in the literature:the Cavallini et al.correlation has the highest accuracy in predicting the heat transfer coefficient inside the smooth tube,the related percentage error and the average prediction error are±8%and 0.56%,respectively;for the micro-fin tube these become±25%and 6%,respectively.

关键词： R1234yf micro-ribbed tube heat transfer coefficient heat transfer enhancement factor

Experimental Analysis of the Performances of Unit Refrigeration Systems Based on Parallel Compressors with Consideration of the Volumetric and Isentropic Efficiency

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Fluid Dynamics & Materials Processing 2020年第3期16卷 489-500页

作者： Daoming Shen Chao Gui jinhong xia Songtao Xue College of Civil Engineering and Architecture Xinxiang UniversityXinxiang453000China Research Institute of Structural Engineering and Disaster Reduction Tongji UniversityShanghai20092China Department of Architecture Tohoku Institute of TechnologySendai982-8577Japan

The performances of a refrigeration unit relying on compressors working in parallel have been investigated considering the influence of the compressor volumetric efficiency and isentropic efficiency on the compression ratio.Moreover,the following influential factors have been taken into account:evaporation temperature,condensation temperature and compressor suction-exhaust pressure ratio for different opening conditions of the compressor.The following quantities have been selected as the unit performance measurement indicators:refrigeration capacity,energy efficiency ratio(COP),compressor power consumption,and refrigerant flow rate.The experimental results indicate that the system refrigeration capacity and COP decrease with a decrease in evaporation temperature,increase of condensation temperature,and increase in pressure ratio.The refrigerant flow rate increases with the increase in evaporation temperature,decrease in condensing temperature and increase in pressure ratio.The compressor power consumption increases with the increase in condensing temperature and increase in pressure ratio,but is not significantly affected by the evaporation temperature.

关键词： Parallel compressor unit evaporation temperature condensation temperature pressure ratio refrigeration capacity energy efficiency ratio(COP)

A New Model for the Characterization of Frozen Soil and Related Latent Heat Effects for the Improvement of Ground Freezing Techniques and Its Experimental Verification

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Fluid Dynamics & Materials Processing 2019年第1期15卷 63-76页

作者： Daoming Shen Hua Si jinhong xia Shunqun Li Xinxiang University 191 Jinsui AvenueXinxiang453000China Tianjin Chengjian University 26 Jinjing RoadTianjin300384China

The correct determination of thermal parameters,such as thermal conductivity and specific heat of soil during freezing,is the most important and basic problem for the construction of an appropriate freezing method.In this study,a calculation model of three stages of soil temperature was established.At the unfrozen and frozen stages,the specific temperatures of dry soil,water,and ice are known.According to the principle of superposition,a calculation model of unfrozen and frozen soils can be established.Informed by a laboratory experiment,the latent heat of the adjacent zone was calculated for the freezing stage based on different water contents in the temperature section.Both the latent and specific heat of water,ice,and particles were calculated via superposition of the weight percentage content.A calculation model of the specific heat of the freezing stage was built,which provides both guidance and theoretical basis for the calculation of the specific heat of frozen soil.

关键词： Freezing construction latent heat frozen soil specific heat

Elevated Kallistatin promotes the occurrence and progression of non-alcoholic fatty liver disease

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Signal Transduction and Targeted Therapy 2024年第4期9卷 1730-1744页

作者： Zhenzhen Fang Gang Shen Yina Wang Fuyan Hong Xiumei Tang Yongcheng Zeng Ting Zhang Huanyi Liu Yanmei Li jinhong Wang Jing Zhang Anton Gao Weiwei Qi xia Yang Ti Zhou Guoquan Gao Department of Biochemistry Zhongshan School of MedicineSun Yat-Sen UniversityGuangzhou 510080China Department of VIP Medical Center the Third Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Physical Examination Center the Third Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510080China Department of Clinical Laboratory Guangzhou First People's HospitalGuangzhou 510080China Guangdong Key Laboratory of Liver Disease Research the Third Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 51008China Department of Health Sciences College of Health SolutionsArizona State UniversityTempeUSA Guangdong Engineering&Technology Research Center for Gene Manipulation and Biomacromolecular Products Sun Yat-Sen UniversityGuangzhou 510080China Guangdong Province Key Laboratory of Diabetology Guangzhou 510o80China Guangdong Province Key Laboratory of Brain Function and Disease Zhongshan School of MedicineSun Yat-Sen UniversityGuangzhou 510080China

Non-alcoholic fatty liver disease(NAFLD)is the most common chronic liver disease worldwide,and the development of nonalcoholic steatohepatitis(NASH)might cause irreversible hepatic damage.Hyperlipidemia(HLP)is the leading risk factor for NAFLD.This study aims to illuminate the causative contributor and potential mechanism of Kallistatin(KAL)mediating HLP to NAFLD.221 healthy control and 253 HLP subjects,62 healthy control and 44 NAFLD subjects were enrolled.The plasma KAL was significantly elevated in HLP subjects,especially in hypertriglyceridemia(HTG)subjects,and positively correlated with liver injury.Further,KAL levels of NAFLD patients were significantly up-regulated.KAL transgenic mice induced hepatic steatosis,inflammation,and fibrosis with time and accelerated inflammation development in high-fat diet(HFD)mice.In contrast,KAL knockout ameliorated steatosis and inflammation in high-fructose diet(HFruD)and methionine and choline-deficient(MCD)diet-induced NAFLD rats.Mechanistically,KAL induced hepatic steatosis and NASH by down-regulating adipose triglyceride lipase(ATGL)and comparative gene identification 58(CGl-58)by LRP6/Gas/PKA/GSK3βpathway through down-regulating peroxisome proliferator-activated receptor(PPARy)and up-regulating kruppel-like factor four(KLF4),respectively.CGl-58 is bound to NF-kB p65 in the cytoplasm,and diminishing CGl-58 facilitated p65 nuclear translocation and TNFa induction.Meanwhile,hepatic CGl-58-overexpress reverses NASH in KAL transgenic mice.Further,free fatty acids up-regulated KAL against thyroid hormone in hepatocytes.Moreover,Fenofibrate,one triglyceride-lowering drug,could reverse hepatic steatosis by down-regulating KAL.These results demonstrate that elevated KAL plays a crucial role in the development of HLP to NAFLD and may be served as a potential preventive and therapeutic target.

关键词： GSK3β inflammation elevated

Synthesis and Activity of Ag-doped Bi2WO6 Photocatalysts

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Synthesis and Activity of Ag-doped Bi2WO6 Photocatalysts

基于ResCNN-BiGRU的四川方言语音识别

中国材料大会2012

作者： Ran Chen Chaohao Hu Shuai Wei jinhong xia Jian Cui Huaiying Zhou School of Materials Science and Engineering Guilin University of Electronic Technology School of Life and Environment Guilin University of Electronic Technology

ISBN: (纸本)9783037856062;3037856068

Ag-doped Bi2WO6 photocatalysts were synthesized by hydrothermal method using from Bi(NO)3·5H2O, NH4VO3 , and AgNO3 and further characterized by X-ray diffraction, Scanning electron microscopy, Energy dispersive X-ray detector (EDS) and UV-Vis diffusion reflectance spectra techniques. The photocatalytic activity of Ag-doped Bi2WO6 photocatalysts was evaluated by degrading RhB (10 mg/L) under visible light irradiation (λ > 420 nm). The results showed that in comparison with pure Bi2WO6 the photocatalytic activity of Ag-doped composite photocatalysts was improved significantly, and the degradation rate of RhB was increased about 26% when the Ag+ dopant concentration was 15%.

关键词： Bi2WO6 photocatalysts Hydrothermal synthesis Ag-doping Visible light.

来源： cnki会议评论

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现代电子技术 2024年第1期47卷 89-93页

作者：谢金洪魏霞新疆大学电气工程学院新疆乌鲁木齐830017

由于基于深度卷积神经网络的语音识别模型中缺乏对特定方言音素特征的提取能力,造成方言发音底层特征部分信息丢失,进而导致方言识别准确率不高、鲁棒性差等问题。针对上述问题,提出一种结合残差网络(RestNet)和双向门控循环网络(BiGRU... 详细信息

由于基于深度卷积神经网络的语音识别模型中缺乏对特定方言音素特征的提取能力,造成方言发音底层特征部分信息丢失,进而导致方言识别准确率不高、鲁棒性差等问题。针对上述问题,提出一种结合残差网络(RestNet)和双向门控循环网络(BiGRU)的模型,该模型以GFCC特征图为输入,同时在残差网络中设计多尺度卷积模块,通过不同大小的卷积核提取特征,然后使用双向门控循环网络捕捉序列数据中的长期依赖关系,最后采用连接时序分类算法进行标签软对齐,实现四川方言语音识别模型。在四川方言语料库上的实验结果表明,提出的模型识别性能优于现有基准模型。

关键词：四川方言音素特征双向门控循环网络多尺度卷积连接时序分类标签软对齐